Dragonflies, known for their striking aerial acrobatics and near 360-degree vision, are one of the oldest groups of winged insects on Earth.
Long before there were dinosaurs, there were dragonflies. That’s one of the things about the ephemeral insects, with their long, slender bodies and gossamer-thin wings, that fascinates entomologist Charl Deacon.
Dragonflies, known for their striking aerial acrobatics and near 360-degree vision, are one of the oldest groups of winged insects on Earth.
“The dragonfly group is ancient, and based on fossil records, their origin dates back around 300 million years ago,” said Deacon, a postdoctoral research fellow at Stellenbosch University.
“The staggering age of the first dragonflies provide us with a look into how life was in the distant past. Contemporary dragonflies retain most body features of ancient dragonflies — except their size — emphasising that they are highly successful insects.”
Dragonflies, a blanket term for both “true dragonflies” and “damselflies”, are a relatively
small group of insects, consisting of about 6 400 species worldwide.
For Deacon, what makes these expert fliers interesting is that they are valuable insects for assessing water and land quality. “Groups of dragonfly species in a defined habitat can tell us a lot about deteriorating environmental conditions and the requirements to restore degraded areas.”
To ensure the long-term survival of dragonflies and other creatures that share their habitats, they must be included more widely in biodiversity conservation efforts and policies. This is the key recommendation from a group of dragonfly experts from 17 countries, including South Africa, Mexico, Australia and the United States.
Their recent review, published in the journal Insect Conservation and Diversity, proposes a five-point action plan to promote dragonflies in freshwater and riverbank conservation.
These are expanding and enhancing dragonfly assessment and monitoring; including dragonflies in standard environmental toxicological risk assessment; learning from dragonflies to improve landscape conservation efforts; ensuring the integration of dragonflies with other plant and animal conservation initiatives; and promoting dragonflies in environmental education.
The scientists said global dragonfly conservation hinges on these five actions implemented across different regions and landscapes.
Deacon noted that although dragonflies are sensitive to changes in their habitats, at the same time, they can recover remarkably well when environmental pressure is lifted. “This means that we can investigate them to learn how we can improve conditions for them, and the other creatures they share their habitats with.”
Dragonflies inspire curiosity and appreciation, he said. “Being surrounded by dragonflies, it is striking to notice their charisma — most dragonflies appear to be attuned to the presence of people in their environments, some would even approach visitors, sometimes seemingly posing for just long enough to show off their beauty.”
About 16% of dragonflies are threatened. Globally, they face relatively similar threats, including habitat loss or modification, water pollution, over-abstraction of water resources and the spread of alien invasive species including fish, amphibians, crustaceans and plants.
Overarching these threats, which often interact, is climate change and its associated extreme weather events.
According to the review, dragonflies could also help measure the success of conservation efforts.
Some examples include the global reduction of human exploitation of wetlands through sustainable land-use practices, beaver reintroduction programmes in Europe, habitat restoration programmes including management of highly invasive alien species, sustainable drainage systems development in cities to enhance resilience to extreme weather and water-related events — creating new dragonfly habitats — and clean energy projects.
South Africa is home to 65 damselfly species and 96 dragonfly species. Population sizes vary from one location to the next, and according to environmental conditions, Deacon said.
“For example, during wet years, dragonfly population sizes may be inflated, while during dry years, dragonfly populations decline. The dragonfly species with specific habitat requirements are most at risk, while those with broader habitat preferences are more resilient, even benefitting from artificial habitats in urban and agricultural areas.”
In South Africa, water pollution, which affects the survival of larvae, and the spread of invasive alien trees in water-adjacent areas, shading out sunny dragonfly habitats, are “particularly worrisome”.
Dragonfly survival depends on both land and water. “They breed in water, and this is where the eggs and larvae are found. But the surrounding land is where the adults are found, and where they mature, hunt, pursue mates, and seek suitable habitat to breed.”
About a third of the species found in South Africa are endemic. “While the northeastern region of South Africa is home to the widest variety of species, most endemic species are found in the Western Cape,” Deacon said.
In their review, the scientists said it is essential to continue and expand the assessment and monitoring of dragonfly population sizes, distributions and the groups of species that live in specific areas.
This information feeds into international conservation prioritisation frameworks and initiatives for understanding conservation risks and declines relative to human pressures and ongoing climate change.
“Monitoring and evaluation during the early stages of conservation programmes are critical to ensure that dragonfly populations, habitats and ecosystems are effectively assessed over time. This approach also helps to quantify threats and measure the level of conservation success. Information gathered through assessment and monitoring must be translated into practical conservation efforts and policy decisions.
By including dragonflies in broader conservation initiatives, conservation policies and management globally will become more effective. “We need policies that focus on overall biodiversity protection, with dragonflies being an important component,” the authors said.
The ability of dragonflies to survive under different environmental conditions depends on the traits or characteristics of individual species.
“For some species, these traits may help them adapt to or benefit from human activities, such as creation of ponds. Others, however, may lack these traits, making them vulnerable to local extinction. While databases on the traits of dragonflies are expanding, other unknown characteristics may also play a role in their ability to adapt to changing environments.”
The researchers called for conservation efforts that link water and land, improve connectivity between habitats, and better maintain water and soil quality. This landscape approach is based on the idea that efforts to protect dragonflies will also benefit other organisms that share similar habitats and requirements.
“Updating regional species lists and developing field guides and digital applications help with species identification. These resources also have great potential to develop knowledge on how they live in ecosystems and interact with plants and animals they share these ecosystems with.”
The scientists emphasised the value of citizen science in enhancing research on conservation and management requirements. “Understanding the cultural role of dragonflies across various regions, will, in turn, spark interest in them, encourage a desire to protect them, and feed into policymaking.”
Deacon noted that insects face multiple difficulties, including habitat loss, habitat transformation, habitat fragmentation/isolation, environmental pollution, over-exploitation of natural resources and the co-extinction of plant and animal species that interact with insects.
They make up a huge proportion of total biodiversity and have important ecological roles. Some are pollinators, some are predators of nuisance species, some are food sources to a variety of animals, and some help regulate decomposition of organic inputs and soil quality.